500E Fuel Problem

[Bryan Harter]

Last night I attempted to put some techron in the tank and upon opening the filler cap, gas exploded out at me. Probably a pint or more. Soaked me!

Car had been sitting for 2 weeks.

Other interesting points:
Last time I drove it, I smelled gas as I exited the vehicle in my driveway.

After changing my fuel soaked clothing, the car cranked a long time before it started.....like there was no fuel in the lines. Fuel pump was buzzing as normal.
I seem to recall it taking a while to start last week as well, but not as noticable as last night.

No puddles under the car today.

Any ideas? What would seemingly cause pressure in the tank and loss of pressure in a line to the engine?